Generally this invention relates to a spray head for use with pressurized containers commonly referred to as pressurized dispensers. More particularly, this invention relates to that portion of the spray head which is operative to mechanically breakup and nebulized to reduce to a fine spray that fluid emerging from the discharge orifice.
Recent interests in ecology have directed attention away from using hydrocarbon or freon compounds as propellants for dispersing consumer oriented products. Compressed gases such as carbon dioxide, nitrogen, or the like are desirable as a propellant medium because of their non-polluting effect on the environment. However, it has been found that certain problems are created by employing a purely gaseous medium as a propellant. The propellant gas, necessarily, is initially placed under relatively high pressures within the container to assure an ample supply of propellant to exhaust the product therewithin. Such pressures may range from 80 to 110 psi. Because of the high initial pressures the discharge orifice is maintained in the range of 0.010 inches in diameter. As the product within the container is discharged the pressure of the propellant continually drops such that the internal pressure is in the range of 40 psi or lower at the time the product is exhausted. Spray heads at this time due to the wide range of pressure variances together with a fixed diameter orifice dimension have resulted in undesirable particle dispersion and pattern over the life of the dispenser. For when the dispenser is first used and pressures are high present spray head design will produce satisfactory nebulization characteristics of the fluid product as it emerges from the orifice, however, as pressure drops these characteristics are acutely affected to such an extent that remaining product pressurized at lower pressures is not effectively broken-up resulting in emergence as large droplets or even a stream.
A general object of the invention is to provide a spray head which will have satisfactory nebulization characteristics over a wide range of fluid product pressures.
Another object of the invention is to provide a spray head having a swirl chamber for use with a container pressured with a purely gaseous medium as a propellant which enables nebulization of fluid, over expected pressure ranges of the propellant.
A still further object of the foregoing is to provide two passages for the conduction of fluid to the swirl chamber, and the swirl chamber having two wall portions symetrically disposed between said passage and a discharge orifice.
A still further object of the invention is to provide that the spray head is constructed of a button portion having a swirl cavity with the wall portions and passages integral therewith, and an enclosing insert having the discharge orifice on said button portion to form the swirl chamber.
Novel features of construction and operation of the device will be more clearly apparent during the course of the following description, reference being had to the accompanying drawings wherein has been illustrated a preferred form of the device and wherein like characters of reference are employed to denote like parts throughout the several figures.